From 2f5cc98102fcab21df1af5e407949be8d8ea9af5 Mon Sep 17 00:00:00 2001
From: krahets <krahets@163.com>
Date: Fri, 19 Apr 2024 19:50:50 +0800
Subject: [PATCH] build

---
 docs/chapter_tree/binary_tree_traversal.md    | 10 +++++++++-
 en/docs/chapter_tree/binary_tree_traversal.md | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/docs/chapter_tree/binary_tree_traversal.md b/docs/chapter_tree/binary_tree_traversal.md
index 172a925dc..f6fa62878 100755
--- a/docs/chapter_tree/binary_tree_traversal.md
+++ b/docs/chapter_tree/binary_tree_traversal.md
@@ -804,7 +804,15 @@ comments: true
 === "Ruby"
 
     ```ruby title="binary_tree_dfs.rb"
-    [class]{}-[func]{pre_order}
+    ### 前序遍历 ###
+    def pre_order(root)
+      return if root.nil?
+
+      # 访问优先级：根节点 -> 左子树 -> 右子树
+      $res << root.val
+      pre_order(root.left)
+      pre_order(root.right)
+    end
 
     ### 中序遍历 ###
     def in_order(root)
diff --git a/en/docs/chapter_tree/binary_tree_traversal.md b/en/docs/chapter_tree/binary_tree_traversal.md
index 68dd05a52..7584e9ba7 100755
--- a/en/docs/chapter_tree/binary_tree_traversal.md
+++ b/en/docs/chapter_tree/binary_tree_traversal.md
@@ -804,7 +804,15 @@ Depth-first search is usually implemented based on recursion:
 === "Ruby"
 
     ```ruby title="binary_tree_dfs.rb"
-    [class]{}-[func]{pre_order}
+    ### 前序遍历 ###
+    def pre_order(root)
+      return if root.nil?
+
+      # 访问优先级：根节点 -> 左子树 -> 右子树
+      $res << root.val
+      pre_order(root.left)
+      pre_order(root.right)
+    end
 
     ### 中序遍历 ###
     def in_order(root)